@m: 42rem;
// 设计稿宽度为420px
.width(@w) {
  width: (@w / @m);
}
.height(@h) {
  height: (@h / @m);
}
.bgC(@color) {
  background-color: @color;
}
.bgI(@url) {
  background-image: url(@url);
  background-repeat: no-repeat;
  background-size: contain;
}
.center(@top:0) {
  display: block;
  margin: (@top / @m) auto;
}
.relative(@top:0,@left:0){
  position: relative;
  top:@top;
  left: @left;
}
.absolute(@top:0,@left:0) {
  position: absolute;
  top: (@top/@m);
  left: (@left/@m);
  overflow: hidden;
}
.fz(@f){
  font-size: (@f/@m);
}
.borderBox{
  box-sizing: border-box;
}
.flex(@content:space-evenly){
  display: flex;
  justify-content: @content;
  justify-items: center;
}
.border-r(@W){
  border-radius: (@W/@m);
}
.zd(){
  z-index: 10;
}
.fix-top(){
  position: fixed;
  top: 0;
  left: 0;
}
.fix-bottom(){
  position: fixed;
  bottom: 0;
  left: 0;
}
.padding(@top:0,@right:0,@bottom:0,@left:0){
  padding: (@top/@m) (@right/@m) (@bottom/@m) (@left/@m);
}
.padding-Top(@top:0){
  padding-top: (@top/@m);
}
.lineH(@h){
  line-height: (@h/@m);
}